The phosphate industry is facing serious environmental problems. This issue is caused by the waste afterthe extraction of the phosphate ore. The waste termed as phosphate washing waste (PWW) was filteredand dried at 105 ºC for 24 h to remove the water. The dried PWW was milled, sieved in a 100 mm sieveand characterized by X-ray fluorescence (XRF). The resulting waste was calcined at 600, 700 and 800 ºC, the calcined and uncalcined waste were investigated by X-ray powder diffraction (DRX), Fourier transform infrared (FTIR), simultaneous differential thermal and thermogravimetric analyses (DSC-TG) and scanning electron microscope (SEM). The PWW was activated with sodium hydroxide (NaOH) and sodium silicate to produce geopolymeric materials. It was found that the calcination temperature and the extra water added to the mixture to assure the good workability play an important role on the development of the system’s workability and compressive strength.

The Centre for Territory, Environment and Construction (CTAC) is a research unit of the School of Engineering of University of Minho (UMinho), recognised by the “FCT – Fundação para a Ciência e Tecnologia” (Foundation for Science and Technology), associated to the Department of Civil Engineering (DEC), with whom it shares resources and namely human resources.

Currently CTAC aggregates 37 researchers holding a PhD of which 27 are faculty professors of the Civil Engineering Department. Read more